More Sacramento-area lakes tighten boat rules to block invasive golden mussels’ spread (2025)

Faced with the rapid spread of golden mussels across California waterways, state and federal officials are imposing strict new measures at Folsom Lake and Lake Clementine to prevent the invasive species from taking hold.

Beginning Monday, all trailered or motorized boats at the two popular Sacramento-area lakes will be required to undergo inspection and a mandatory 30-day quarantine before launching.

“California State Parks is working with the U.S. Bureau of Reclamation and numerous state agencies to take critical steps to prevent golden mussels from infesting Folsom Lake and Lake Clementine,” said Mike Howard, superintendent of Folsom Lake State Recreation Area. “We thank boaters for their understanding as we implement the new procedures and are working to make the inspection processes as efficient as possible.”

Golden mussels, native to Asia, were first detected in California waters last fall in the Port of Stockton. Since then, they have spread rapidly through connected waterways, reaching as far south as Bakersfield. Officials warn that the freshwater mollusks threaten California’s water infrastructure, power systems and aquatic ecosystems by clogging pipes, outcompeting native species and damaging boats by attaching to hulls and clogging engines.

“Golden mussels are a greater threat to Tahoe than other aquatic invasive species,” said Dennis Zabaglo, aquatic invasive species program manager for the Tahoe Regional Planning Agency, which recently adopted mandatory decontaminations for all visiting motorized boats in the Sierra waterway. “Boaters and paddlers have a key role in protecting the waters they enjoy.”

Down the hill, State Parks officials emphasized the stakes were high. Without intervention, golden mussels could disrupt water deliveries from the reservoirs and compromise power generation at Folsom Dam.

“These prevention measures are a far better alternative to closing the lakes to vessels or a golden mussel infestation,” Howard said.

The Folsom and Clementine program mirrors restrictions adopted across Northern California with boaters wishing to launch having a red quarantine seal for at least 30 days after a mandatory inspection. Boats exiting the lakes can be sealed by inspectors to avoid future quarantines, provided the cabled seal remains intact.

Trailered vessels, meanwhile, will not be permitted on Lake Natoma, and only hand-launched watercraft will be allowed.

On all three waterways, officials said all boaters, including paddlers and rowers, must arrive with their watercraft clean, drained and dry.

Similar precautions are already in place at Rancho Seco Lake in southeast Sacramento County, where the Sacramento Municipal Utility District enacted emergency rules late last month.

Boaters across the region are urged to follow the “Clean, Drain and Dry” guidance and check local rules before visiting lakes and reservoirs. Details for the Sacramento-area program, including inspection locations and hours, are available at parks.ca.gov/FolsomLakeGoldenMussels.

This story was originally published April 8, 2025 at 8:25 AM.